Along with science and technology development, human-computer interaction devices are more and more widely used-spread in daily life, such as touch screens, electronic whiteboards, etc, one kind of which is infrared touch screens. Because ambient light changes instantly in various location and time, it causes light interference while the infrared receivers in infrared touch screens are receiving the infrared light emitted from the corresponding infrared emitters, which influences the detecting precision of infrared touch screens. This is an urgent issue to be solved.